Balloon catheters, in particular the balloons they carry, are used for a variety of medical applications including: delivery of implantable medical devices such as stents and stent grafts, for vessel dilatation, angioplasty, valvuloplasty and so on. A number of these procedures involves risk to the integrity of the balloon, which can tear or burst as a result of the stresses to which it is put and/or the pressure to which the balloon is inflated. In addition, such balloons, which are typically made from a polymer material for flexibility and compressibility, are virtually invisible under imaging. Lack of visibility of the balloon causes difficulties in controlling the deployment operation. To counter this, it is known to inflate medical balloons with a contrast agent. This does not, however, resolve the lack of visibility of the balloon prior to its inflation. Moreover, contrast media is relatively viscous, leading to lengthened inflation and deflation times, as well as not being particularly biocompatible and thus not ideal in situations where the balloon may burst.
While high strength balloons have been proposed, their structures can be such as to add bulk and lose flexibility, which can lead to reduced wrappability and performance of the balloon.
Examples of prior art balloon catheters are disclosed in US 2011/0160661, EP 0 768 097, U.S. Pat. Nos. 5,776,141, 7,824,517 and US 2009/0306769.